A properly designed and sized hydronic
heating system will insure your comfort and save many dollars on
installation and operating costs.
There are a lot of internet sites offering boiler sizing information. Almost
all use rules of thumb for sizing the boiler and only a few tell you how many feet
of baseboard convectors or radiant piping should be installed in each room
in order to assure even heat distribution throughout the home. Its not
unusual to find a 140,000 btuh boiler along with 200 linear ft of baseboard
convectors installed in a 2000 square foot home, although an 80,000 btuh
boiler and 100 linear ft of baseboard may have been more than adequate.
The savings in equipment alone could be well over
$1000 if only a heat loss calculation is performed.

If you are replacing only a boiler and
leaving the existing baseboard or radiant floor piping in place, then a
simple whole house (block load) calculation will determine the new boiler
size.

WHOLE HOUSE HEAT LOSS CALCULATION

This load calculation indicates 53,687 btuh
are needed to heat the sample home. Therefore a boiler with an output
of at least 53,687 btuh must be chosen.

If you are replacing the entire system,
boiler plus radiators or radiant flooring, then a room-by- room calculation
must be performed. This calculation will determine the correct amount of
baseboard or floor piping to be installed in each room.

ROOM-BY-ROOM CALCULATION

The illustration above indicates 6223 btuh are needed to heat the kitchen. If the baseboard manufacturer's
specifies 580 btuh/ft., then 11 feet of baseboard will be needed in the
kitchen (6223/580 = 10.7). Likewise, the living room will need 7500 btuh
to keep it warm, therefore 13 feet of baseboard will be needed (7500/580 =
12.9).

A heat loss/gain calculation is not rocket
science. One can be preformed by anybody capable of calculating the square
feet of a homes' walls, floors, ceilings and windows. Below is a link to an
extremely affordable (only $39)
HVAC load calculation program that will produce a heat
loss calculation plus a heat gain calculation (sizes A/C) and operating cost
estimator. You will be able to compare one system to another or one fuel vs
another. Its well worth looking into.